package com.kfy.observerdemo.Observer;

/**
 * @ProjectName: ObserverDemo
 * @Package: com.kfy.observerdemo
 * @Author: K.F.Y
 * @Date: 2021/5/8
 */
public interface Observer {

    //订阅主题
    void subscribe(Subject subject);

    //取消订阅
    void unsubscribe(Subject subject);

    //更新
    void update(Subject subject);

}
